Surgical course
The implemented epicardial leads were either unipolar non-steroid-eluting or bipolar steroid-eluting. The type of epicardial lead to be applied for a patient was selected based on the preference and experience of the surgeon, discussion with electrophysiology team, and availability of the lead. Regarding availability of the leads, it should be noted that bipolar steroid-eluting leads were less available in recent years in Iran due to the sanctions and being expensive. However, since we enrolled all patients with epicardial lead implantation and considered patient and lead factors in our multivariate analysis, lead availability did not cuase a bias. Several surgeons performed the surgeries, who are well experienced regarding lead implementation. Epicardial leads were implanted through a midline sternotomy, lateral thoracotomy, or subxiphoid approach. These approaches were selected according to the patients’ cardiac anatomy and position, their prior or concurrent operations.